My DPhil research lies in examining the Antarctic Circumpolar Current from a Potential Vorticity perspective. I am looking at the effect of bottom topography on steering the ACC, particularly through Drake Passage where it makes a large northward excursion. To study this, I am building a simple / fundamental ACC model based on PV dynamics and a linear relation between PV and density. I am also searching for complementary processes in SOSE, which is a state estimate of the Southern Ocean that knows about the fluid dynamics and PV conservation yet is constrained by observations.

During my MSc, under Oleg Saenko, I explored a new parameterization of small-scale turbulence (vertical / diapycnal mixing) related to parameterized mesoscale eddy activity in coarse resolution ocean general circulation models. The cascade of energy between the large-, meso-, and small-scales is not well understood. The most common eddy parameterization allows a certain amount of energy to “leak away” and dissipate, though I believe, as it has been proposed, that this energy could cascade to the small-scale and support vertical mixing. If allowed to do so, the abyssal oceanic circulation that is simulated changes drastically. Moreover, its response to changing climatologies is different. Previous studies (theory and modelling) showed the lower limb of the meridional overturning circulation would weaken under stronger southern hemisphere westerly winds (which is expected under 21st century anthropogenic climate change). When the above energy pathway is included, however, in fact the lower MOC strengthens under stronger westerlies. This has significant implications for long-term climate feedbacks.